Ainslie retires from America's Cup trials race with damage

It's been a rough spring for British sailing star Sir Ben Ainslie in the lead-up to the America's Cup on Bermuda's Great Sound.

He's struggled for speed on his 50-foot foiling catamaran and been involved in three crashes, including a spectacular one on the first day of the qualifiers that almost sank his boat.

Monday brought the biggest setback yet, when the wing sail on the British boat was seriously damaged in the opening race of the challenger semifinals, forcing him back to shore with two quick losses to Emirates Team New Zealand.

Ainslie's Land Rover BAR crew pulled up on the third of seven legs after the camber arm in the high-tech wing sail broke. He radioed to the race committee that he was withdrawing. The race was black-flagged, allowing the Kiwis to collect a point without sailing the whole course.

The Brits tried to get back to the dock to replace the wing. Because the craft couldn't sail, it had to be pushed backward and sideways by support boats, costing the team 20 to 30 minutes and making it impossible to get back out for the next race.

Team New Zealand merely had to start the second race and the race committee immediately black-flagged it, giving the Kiwis a 2-0 lead in the best-of-9 series.

''It's a tough day for the team to lose two races like that so early on in the piece, considering what's at stake here,'' Ainslie said. ''But I've got a lot of belief in the team that this is something we can come back from. ... We'll be back out tomorrow pushing hard.''

He said the boat had just rounded the downwind mark and gotten on the wind when there was a ''big crunching sound coming out of the wing. In those situations it's awfully tempting to just keep plowing on and ignore it, but it was a pretty loud bang. We knew something fundamental was wrong.''

Ainslie called it a ''technical bit of kit so I can't talk too much about exactly what did break, but it has something to do with the wing-control system, and a breakdown there that was pretty catastrophic.''

He said the team planned to fix that wing sail and use it in two scheduled races against the Kiwis on Tuesday.

''These boats are incredibly high-performance, technical racing machines and we're pushing them to the limits,'' Ainslie said. ''This was a breakdown we haven't experienced before and we've sailed in stronger conditions than we had today.''

Team New Zealand skipper Peter Burling said it's ''never something you want to look across at your competitor and know they've got some pretty serious damage on board. We felt we were in for a real battle today and obviously it was a bit of a shame there wasn't much of a battle.''

Earlier this spring, Ainslie hit the dock while returning from training in March; hit the back of Emirates Team New Zealand's boat in a practice race, causing serious damage that took the Kiwis three days to fix; and then slammed into SoftBank Team Japan during the start of a race in the first round robin, punching a hole in one of the hulls. The boat nearly sank as it returned to the dock after the race.

Ainslie has rallied before, both in winning Olympic gold medals and in helping Oracle Team USA win eight straight races to come back from an 8-1 deficit against Team New Zealand in the 2013 America's Cup on San Francisco Bay.

He is hoping to become the first Englishman to hoist the Auld Mug in victory. The British lost the silver trophy to the schooner America in 1851 and have failed in multiple attempts to win it back.

Ainslie is the most successful sailor in Olympic history, with four gold medals and one silver. He was knighted several months after winning his fourth straight gold medal in home waters in 2012.

In the other semifinal, SoftBank Team Japan and Sweden's Artemis Racing each took a comeback victory. Team Japan won the first race by 23 seconds and Artemis the second race by 29 seconds.

In the second race, Team Japan had a bad gybe and buried its bows in the water just as the crew was crossing the boat. Skipper Dean Barker took a tumble on the trampoline.

One challenger will emerge to face two-time defending champion Oracle Team USA in the America's Cup match starting June 17.